Answer:
a)Taking into consideration Newton’s second law, we know that
Net_Force = mass * acceleration
Since the box is pulled at constant speed, the acceleration is equal to zero.
This means that
Net_Force = 0 N
b) Force of friction
The net force is equal to the sum of all forces,
Net_Force = Force_applied - Friction
We found that Net_Force = 0, which means
Friction = Force_applied = 48 N
c) If the box comes to a stop. And the applied force becomes zero, the friction force becomes also zero.
Friction = 0 N